Each subevent uses a syntax appropriate to its intended use. Both RF subevents use (in this case) identical schema, but occur with different flip angles ("FA") and time offsets ("t_o"). The gradient subevent assumes ("t_o":0), and hence is omitted. Timings for the gradient subevent are given in a conventional way, in terms of rise ("t_r"), fall ("t_f") and plateau ("t_p") times [1]}, as well as a maximal amplitude ("ampl"). Gradient pulse amplitudes are given as an array of three values corresponding to maximal amplitudes in \(x\) , \(y\)  and \(z\)  global coordinates. We indicate the spacing of these pulses with "t_bdel", using the \(\Delta \)  convention [2]}. We indicate the relative polarity of the paired pulses with "pol", with 1 and \(-1\)  denoting identical and opposite polarity, respectively.
